Single acting reciprocating pump with tandem pistons



Feb. 22, 1955 L.. L. MccoNNoHlE SINGLE ACTING RECIPROCATING P UMP WITH TANDEM PISTONS 2 Sheets-Sheet l Filed Jan. 29, 1951 m. w VL m ATTORNEY.

SINGLE ACTING RECIPROCATING PUMP WITH TANDEM PIsToNs Filed Jan, 29, 1951 Feb. 22, 1955 L. MGCONNOHIE 2 Sheets-Sheet 2 IN VEN TOR. e1/z' L McCon/:Q/'e @M @mi A TTORNE Y,

United States Patent() SINGLE ACTING RECIPROCATING PUMP WITH TANDEM PISTONS Levi L. McConnohie, Galesburg, Mich.

Application January 29, 1951, Serial No. 208,286

Claims. (Cl. 103189) This invention relates to improvements in single acting reciprocating pump with tandem pistons.

The principal objects of this invention are:

First, to provide a reciprocating pump of the single acting type which approaches the performance of a louble acting pump in the amount of liquid it will deiver.

Second, to provide a single acting reciprocating pump having a high operating eiciency.

Third, to provide a single acting reciprocating pump with two or more axially arranged pump chambers so that each stroke of the pump delivers a greater amount of liquid than a single piston pump having the same stroke and diameter.

Fourth, to provide novel means for mounting a secondary piston on the pump rod of a reciprocating pump so that the one pump rod may function in two pump chambers simultaneously.

Fifth, to provide a novel arrangement of cylinder check valve and piston check valve which permits a secondary piston to operate in a pump cylinder above a lower piston and pump chamber to increase the output of the pump.

Sixth, to provide a reciprocating pump with a hollow piston rod which conducts liquid from a lower pump chamber upwardly through an auxiliary pumping chamber to combine with the output of liquid delivered by an auxiliary piston in the upper pump chamber.

Other objects and advantages of my invention will be apparent from a consideration of the following description and claims.

The drawings, of which there are two sheets, illustrate a practical and highly efficient form of my pump.

Fig. l is a fragmentary longitudinal cross sectional view through my pump illustrating the parts on the upstroke of the pump.

Fig. 2 is a fragmentary longitudinal cross sectional view through the pump cylinder illustrating the reciprocating parts in elevation and on the downstroke thereof.

Fig. 3 is an enlarged fragmentary longitudinal cross sectional view through the upper pump chamber and upper piston of my pump with the reciprocating parts illustrated on the downstroke.

My pump is an improved form ofthe familiar reciprocating type and includes generally a cylinder 1 arranged to be lowered into a well casing 2 to be irnmersed in liquid at least up to va point over the middle of the cylinder, as indicated at 3 in Fig. 1. The upper end of the cylinder is threaded as at 4 to receive a coupling connection to a drop pipe 5. In place of the drop pipe 5, a casing seal may be connected to the upper end of the pump cylinder to support and seal the same to the inside of the casing, as will be readily understood. Intermediate of its ends, kthe cylinder 1 is divided by a divider block 6 so that the cylinder forms an upper pumping'chamber 7 and a lower pumping chamber 8. The lower end of the cylinder is provided with a familiar form of inlet valve including the valve housing 9 and weight biased check valve 10 for admitting liquid through the ports 11 to the lower end of the lower pumping chamber 8. The dividerblock 6 forms inlet passages 12 to the lower end of the upper pumping chamber 7, and the passages 12 are controllled by a check valve 30, as will be described present y.

Reciprocatingly mounted in the cylinder 1 is a hollow tubular piston rod 13 `which extends through the "ice divider block 6 and is connected at its upper end toha reciprocating pump rod 14. The lower end of the plston rod 13 carries a chambered housing 15 having ports 16 formed therethrough and communicating between the interior of the piston rod and the upper portion 17 of the lower pump chamber 8. A tubular nipple 18 threaded into the lower end of the housing 15 forms a lower piston check valve seat with which the check valve 19 cooperates in a familiar fashion. The nipple 18 is provided with an outwardly extending collar or shoulder 20 at its lower end which forms an abutment opposed to the lower end of the housing 15 for clamping a pair of flexible annular piston rings or pump leathers 21 to the housing 15. An annular spacer 22 operates the rings in a well-known manner. The lower end of the piston rod and the lower pumping chamber 8 are thus provided with a single acting piston and valves which operate to deliver water from the lower pumping chamber. The lower piston functions in the same manner as previously well-known pistons except that on the upward delivery stroke, the liquid is forced inwardly through the ports 16 and up through the tubular piston rod 13 instead of being lifted directly upwardly above the piston.

Considering in greater detail the construction of the divider block 6 and upper inlet ports 12, it will be noted that the divider block 6 is an annular cylindrical member with internal and external threads on each end. The divider block is annularly grooved near its middle, as at 23, and the upper inlet ports 12 extend axially upwardly from this groove through an upper cylinder check valve seat 24. It will be understood that the passages 12 are angularly spaced completely around the divider block.

The pump cylinder 1, which is divided by the divider block, is actually two cylindrical tubes 25 and 26 which are threaded on the external threads of the divider block.

The internal thread at the upper end of the divider block engages and supports a tubular guide sleeve 27 which projects upwardly above the check valve seat 24 and is provided with an outturned ange 28 forming an abutment for the upper cylinder check valve spring 29. An annular valve element 30 is slidably supported around the sleeve 27 and spring biased toward engagement with the seat 24 by the spring 29. The inner surface of the guide sleeve 27 forms a bearing for the reciprocating piston rod 13.

The lower end of the divider block 6 is provided with an interior annular shoulder 31 against which the annular packing 32 is abutted. The packing 32 is compressed against the shoulder and around the piston rod by a packing gland 33 threaded into the lower end of the divider block. The upper pumping chamber 7 and the'lower pumping chamber 8 are thus separated against the passage of liquid therebetween except as liquid is permitted to flow through the tubular piston rod 13, as will be described.

Turning now to the piston structure located in the upper pumping chamber 7 and connected to the top of the piston rod 13, it will be noted from Fig. 3 that the piston rod 13 is provided with an extension coupling 34. To permit easy assembly and disassembly of the upper piston structure, the extension'coupling 34 consists of two axially aligned and threadedly connected hollow nipples 35 and 36. The lower nipple 36 is threadedly connected to the upper end of the piston rod 13 and is provided with an annular outwardly projecting abutment 37 supporting an annular deformable sealing ring 38. The wall of the lower nipple 36 is pierced by a plurality of piston valve inlet ports 39 located just above the sealing ring 38. The upper nipple 35 is provided with an annular outwardly extending ange 40 forming an abutment for the upper piston check valve spring 41. The outer surfaces of the nipples 35 and 36 are of the same diameter to slidably support an upper piston structure generally indicated at 42 and biased toward engagement with the sealing ring 38 by the spring 41. The upper end of the upper nipple 35 is transversely bored in a plurality of outlet ports 43 and is provided with a threaded collar 44 for connection to the pump rod 14, as illustrated in Fig. 1.

Acheck valve to close olf the ports 39.

3 ,n The upper piston structure 42 .consists of .an...inn r sleeve 45 slidably engaging the nipples 35 and 36 and provided with an annular outwardly extending flange 46 on its lower end. A packing ring 47 is threaded on the upper endof the sleeve l5 and serves to clamp a pair of annular piston rings or leathers 48 against the iiange 46 and a ring 49. The spacing ring 49 separatesf the Yrings 48 in a well-known manner. The packing ring. 47,is further provided with an upwardly facing shoulder 50 forming a seat forthe spring 41.y It willthus be seen that the upper piston t2 is capable of limited axial sliding motion relative tothe piston rod and that in ktlteplowered position of the piston, the piston itself will function as a They operation of my pump is most clearly understood from a comparison of Figs. l` and 2. On the upstroke of the pump rod 14 and piston rod 1 3, as shown in Fig. l, the lower cylinder check valve l and the upper cylinder check valve 30 will be open due to the suction created by thepistons in the pumping chambers 7 and 8. The lower piston check valve 19 will be closed and the upper piston 42 will be in its lowered position closing the port 39. In this condition of the pump structure, liquid vwill be drawn into the` two pumping` chambers Ythroughthe inlet ports 1l and i2.l On the succeeding downstrokeof the pump rod i4,V the cylinder check valves 1l) land 3i) will naturally close, and the pressure of the pistons on the liquid in the lower ends of the pumping chambers will causethe piston check valve 19 to open and the upper piston 42 to move upwardly opening the ports 39. In this condition of the pump parts the liquid which had been drawn into the lower ends of the pumping chambers will be transferred to the upper ends thereof as the pistons move downwardly through the pumping chambers. Liquidl from the lower end of the upper chamber 7 will passinwardly through the ports 39 and upwardly through the hollow nipples 35 and 36 and through the ports 43 to the upper end ofthe upper chamber.

On the next succeeding upstroke 'of the pump parts, liquid which has been trapped in the upper portion 17 of the lower pumping chamber will be forced inwardly through the openings 16 and upwardly through the hollow piston rod 13 to the ports 43 and the uppertend of the upper pumping chamber. Simultaneously liquid trapped in the upper end of the upper pumping chamber 7 will be delivered upwardly along with the liow from the lower pumping chamber through the drop pipe for delivery to the top of the Well., It should thus be apparent that f or a given diameter of pump casing and given length of stroke, my pump structure is capable of displacing upwardly a substantially greater amount of liquid than a single piston of the same size and stroke.

Having thus described my inventionk what I claim as new and desire to secure by Letters Patent is:

l. A reciprocating pump comprising an elongated pump cylinder, a divider block in said cylinder dividing the same into upper and lower pump chambers, said divider block having an upper inlet passage formed therein and opening from the outside of said cylinder into the bottom of the upper of said chambers, a tubular piston rod reciprocable in said chambers and sealingly engaged with said divider block, a lower cylinder check valve `positign'netl nea'r the bottom of said cylinder to admit liquid into the bottom of the lower of said chambers, an uppercylinder check valve sleeved around said piston rod and cooperative with said upper inlet passage to close the same, a lower piston reciprocable in said lower chamber and xedly connected to the lower end of said piston rod, a valve controlled passage opening between the upper and lower faces of said lower piston, said piston rod opening at its lower end to the upper portion of said lower chamber, an upper piston positioned around said rod in said upper chamber and mounted for limited relative axial 'sliding motion with respect Ato said piston rod and sealed therearound, said piston rod having an `opening formed therein and communicating from the interior of the rod to said upper chamber and positioned lto be closed bv said upper piston in the lower position of the upper piston relative to said piston rod, and means at the upper end of said piston rod forconnecting the same to -a reciprocable pump rod, said piston rod opening at its upper end to the upper portion of said upper chamber. y

A 2. A reciprocating pump comprising an elongated pump cylinder, a divider block in said cylinder 'dividing thes'ame ,intQnpperandlower.pump chambers, said divider block having an upper inlet passage formed therein and opening from the outside of said cylinder into the upper of said chambers, a tubular piston rod reciprocable in said chambers and extending in sealed relationship through said divider block, a lower cylinder check valve positioned near the bottom of said cylinder to admit liquid into the bottom of thelower of said chambers, an upper cylinder check valve cooperative with said upper inlet passage, a tubular bearing for said rod carried by said divider block and projecting thereabove, @Spring compressed between said bearing and said upper check valve, a lower piston reciprocable in Vsaid lowe'r chamber and iixedly connected to the lower end kof said pistonhrod, av,valve controlled passage opening between the upper and lower faces of said lower piston, said piston rod opening at its lower end to the upper portion of said lower chamber, an upper piston positioned aroundl saidrod in said upper chamber and mounted for limited relativev axiall slidingfmotion with respect to said piston rod, said piston rod having an opening formed therein and communicating from the interiorof the rodto said upper chamber arrangedtobe closed by saidupper piston in the lower position of the upper piston relative to said piston rod, a spring compressedV between the top of said'piston rod and the top of said upper piston, andmeans at the upperendof said piston rod for connecting the same to a reciprocable pump rod, said piston rod opening at its upper end to the upper portion of said upper chamber. y

. v3. A reciprocating pump comprising an elongated pump Cylinder, a divider block in said cylinder 'dividing the same into upper and lower pump chambers, means forming an upper inlet passage from the outside of said cylinderinto the bottom of the upper of said chambers, a tubular piston rod reciprocable in said chambers 'and extending in sealed 'relationship through said divider block, a vlower cylinder check valve positioned near the bottom of said cylinder to admit liquid into the bottom of the lower of said chambers, an upper lcylinder check valve cooperative with said upper inlet passage, a lower piston reciprocable in said lower chamber and fixedly connected to the lower end of said piston rod, a valve controlled passage opening between the upper and lower faces of said lower piston, said piston rod 'opening at its lower end to the upper portion of said lower chamber, an upper piston positioned around said rod in said upper chamber and mounted for limited relative axial sliding motion with respect to said piston rod, said piston rod having an opening formed therein and communicating from the interior of the rod to said upper chamber and positioned to be closed by said upper piston in the lower position of the upper piston. relative to said piston rod, and means at the upper end of said piston rod for connecting the same to a recipro'cable pump rod. said piston rod opening at its upper end tothe upper portion ofrsaid upper charr'ibe'r.V v Y 4, A reciprocating pump adapted to be immersed in a well 'comprising a tubular pump cylinder divided into upper and lower tubular members. a divider block joining said tubular members and deiipint7 al central vplunger passage opening therebetween. said dividerblook further having'an upper inlet passage formedl therein and opening from the exterior of the block towithin said upper tubularni'eymber with a valve seat at tljieinner endpof vthe inlet passage, a plungerfguidefbearing extending upwardly from said block and having an external abutment at ,itsy upper end`an upper cylinder lcheck valve guidinglv supported by` said guide bearing, a spring between 4said abutment and said valve biasing the valve toward engagementvwith s'a'id seat, alower cylinder check valvepositoned in the bottom of s'aid lower tubular member, a tubularfplunizer reciprocablein said guide andtubular members and sealed 'aroundits outside with respect to, saiddivderblock, 'a lower piston 'carried bythe lower end of said plunger and having alower piston inlet passage formed therein opening between the upper and lower'ifaces thereof, al vfer piston check valve carried bv said lower piston and weight biased to close said lower piston inlet passarzesaid piston having 'aloWer outlet openingL yformed therein Atrom the upper faceythereofito the lower end Vof said plunger an upper'piston lsleeved around the upper end of saidplunger and within said upper tubular member, an annular collar secured D `round ineens, biasing sa i (0 sealing rangement Wths'a'ld collar, said plunger h`av1n'g' a transverse passage formed therethrough and positioned above said collar whereby said upper piston constitutes an upper piston check valve to close said passage in the lower position of the upper piston relative to the plunger, said plunger further having an opening formed therein from the interior thereof to the upper end of said upper tubular member, means at the upper end of said plunger for connecting the same to a reciprocable pump rod, and means at the upper end of said pump cylinder for connecting the same to a drop pipe.

5. A reciprocating pump adapted to be immersed in a well comprising a tubular pump cylinder divided into upper and lower tubular members, a divider block joining said tubular members and defining a central plunger passage opening therebetween, said divider block further having an upper inlet passage from the exterior of the block to within said upper tubular member with a valve seat at the inner end of the inlet passage, an upper cylinder check valve guidingly supported by said divider block and biased toward engagement with said seat, a lower cylinder check valve positioned in the bottom of said lower tubular member, a tubular plunger reciprocable in said tubular members and slidably in sealed relationship through said divider block, a lower piston carried by the lower end of said plunger and having a lower piston inlet passage formed therein opening between the upper and lower faces thereof, a lower piston check valve carried by said lower piston and biased to close said lower inlet passage, means forming a lower outlet opening from the upper face of said lower piston to the lower end of said plunger, an upper piston sleeved around the upper end of said plunger and within said upper tubular member, means biasing said upper piston downwardly, said plunger having a transverse passage formed through its wall and positioned whereby said upper piston constitutes an upper piston check valve to close said passage in the lower position of the upper piston relative to the plunger, said plunger further having an opening formed therein from the interior thereof to the upper end of said upper tubular member, means at the upper end of said plunger for connecting the same to a reciprocable pump rod, and means at the upper end of said pump cylinder for supporting the same within a Well casing and sealing the upper end of the pump cylinder from the interior of the lower end of the casing.

6. A reciprocating pump comprising a pump cylinder divided into upper and lower chambers, inlet passages opening to the bottoms of each of said chambers, check valves arranged to close said passages, a tubular piston rod reciprocable in said chambers and extending therebetween, a lower piston carried by said piston rod within said lower chamber and having a port formed through the piston and a piston check valve coacting with the port to permit the flow of liquid between the faces of the piston on the down stroke thereof, said piston rod opening to said lower chamber above said lower piston, an upper piston carried by said piston rod within said upper chamber and mounted for limited sliding motion on said rod, means including a portion of the length of said rod forming an upper piston check valve passage opening between the faces of said upper piston and open on the down stroke of said upper piston, said upper piston constituting a check valve element for said upper piston check valve passage, and means for connecting said piston rod to an actuating pump rod, the upper end of said piston rod opening to said upper chamber above said upper piston.

7. A reciprocating pump comprising a pump cylinder divided into upper and lower chambers, inlet passages opening to the bottoms of each of said chambers, check valves arranged to close said passages, a tubular piston rod reciprocable in said chambers and extending therebetween, a lower piston carried by said piston rod within said lower chamber and having a port formed through the piston and a piston check valve coacting with the port to permit the flow of liquid between the faces of the piston on the down stroke thereof, said piston rod opening to said lower chamber above said lower piston, an upper piston carried by said piston rod within said upper chamber, means forming an upper piston check valve opening between the faces of said upper piston and open on the down stroke of said upper piston, and means for connecting said piston rod to an actuating pump rod, the upper end of said piston rod opening to said upper chamber above said upper piston.

8. A reciprocating pump including a pump cylinder, a tubular piston rod reciprocable in said cylinder and opening at its upper end to within the cylinder, upper and lower abutments on said piston rod located below the open upper end of the rod, an outlet port formed through the wall of said piston rod between said abutments, a piston slidably mounted around said piston rod between said abutments and slidably engaging the inside of said cylinder, means biasing said piston into engagement with the lower of said abutments to close said outlet port, and means for connecting a pump rod to said piston rod, said piston rod extending through the bottom of said cylinder and being operatively connected with a second piston, and a second cylinder disposed below said rst cylinder and piston and operatively associated with said second piston, said second cylinder and second piston delivering upwardly through said tubular piston rod.

9. A reciprocating pump including a pump cylinder, a tubular piston rod reciprocable in said cylinder and opening at its upper end to within the cylinder, upper and lower abutments on said piston rod located below the open upper end of the rod, an outlet port formed through the wall of said piston rod between said abutments, a piston slidably mounted around said piston rod between said abutments and slidably engaging the inside of said cylinder, means biasing said piston into engagement with the lower of said abutments to close said outlet pot, and means for connecting a pump rod to said piston ro 10. A reciprocating pump comprising, a cylinder with a tubular plunger reciprocable therein, a plurality of pistons carried by said plunger at spaced intervals therealong and cooperative with the inner surfaces of said cylinder, at least part of said pistons being mounted for limited axial motion relative to said plunger, means positioned in said cylinder and between said pistons dividing said cylinder into a plurality of pumping chambers and sealingly engaged with said plunger, pump chamber inlet passages opening to the bottoms of said chambers, check valves cooperative with said chamber inlet passages, transfer passages opening between the faces of each of said pistons, piston check valves cooperative with said transfer passages, an outlet passage opening from the interior of said plunger to the upper portion of the lower chamber of said plurality of chambers and above the piston therein, and a discharge passage opening from the upper end of said plunger to the upper portion of the upper chamber of said plurality of chambers whereby liquid displaced from the lower chamber by the piston therein is directed upwardly through said plunger to the upper portion of the upper chamber for further delivery along with liquid displaced from the upper chamber, each piston that is movable relative to the plunger constituting the piston check valve element of the transfer passage associated therewith.

References Cited in the le of this patent UNITED STATES PATENTS 899,784 Blanchard Sept. 29, 1908 1,104,962 Clark July 28, 1914 1,272,737 Walker July 16, 1918 1,573,823 Gray Feb. 23, 1926 1,665,639 Patterson Apr. 10, 1928 2,227,122 Brittain Dec. 13, 1940 2,513,869 Hoffer July 4, 1950 

